class_docstr: Mixin for testing batch training.
  
  Inherit this after _TestTraining to enable test cases for batch training.
code: def _test_batch_training(
      self, gpu, steps=5000, load_model=False, require_success=True
  ):
      random_seed.set_random_seed(1)
      logging.basicConfig(level=logging.DEBUG)
  
      env, _ = self.make_vec_env_and_successful_return(test=False)
      (
          test_env,
          successful_return,
      ) = self.make_vec_env_and_successful_return(test=True)
      agent = self.make_agent(env, gpu)
  
      if load_model:
          print("Load agent from", self.agent_dirname)
          agent.load(self.agent_dirname)
          agent.replay_buffer.load(self.rbuf_filename)
  
      # Train
      train_agent_batch_with_evaluation(
          agent=agent,
          env=env,
          steps=steps,
          outdir=self.tmpdir,
          eval_interval=200,
          eval_n_steps=None,
          eval_n_episodes=5,
          successful_score=1,
          eval_env=test_env,
      )
      env.close()
  
      # Test
      n_test_runs = 5
      eval_returns = batch_run_evaluation_episodes(
          test_env,
          agent,
          n_steps=None,
          n_episodes=n_test_runs,
      )
      test_env.close()
      n_succeeded = np.sum(
          np.asarray(eval_returns) >= successful_return
      )
      if require_success:
          self.assertEqual(n_succeeded, n_test_runs)
  
      # Save
      agent.save(self.agent_dirname)
      agent.replay_buffer.save(self.rbuf_filename)
  
imports: import logging
  import os
  import tempfile
  import unittest
  from chainer import testing
  import numpy
  import chainerrl
  from chainerrl.experiments.evaluator import batch_run_evaluation_episodes
  from chainerrl.experiments import train_agent_batch_with_evaluation
  from chainerrl.experiments import train_agent_with_evaluation
  from chainerrl.misc import random_seed
label_desc: Use image node_id 2 for calling the _TestBatchTrainingMixin obj's underlying member method code with example usage: obj._test_batch_training(gpu, steps, load_model, require_success) without return types